JPH02228102A - On-vehicle diversity antenna - Google Patents

Abstract

PURPOSE:To take the impedance matching and to eliminate the deterioration of a diversity effect by setting the center coaxis of a feed use feeder cable of a monopole antenna and a connecting position of a ground side irrespective of whether the antenna is contained or stretched out. CONSTITUTION:A coaxial feeder cable 7 for a sleeve antenna 1 and a rack cable 20 provided in parallel to the cable attached to a connecting member 6 penetrate the inside of a cylindrical tube 38 and a containing tube 55 being a monopole antenna 2, and by its cable 20, the antenna 1 and the antenna 2 are contained in the containing tube 55 or stretched out of the containing tube 55. A driving part 65 constitutes an antenna driving device for leading in or leading out the cable 20. The driving part 65 is the same as a driving mechanism of the existing radio use motor antenna. However, it is constituted of a winding part 66 for winding the cable 20 and the cable 7 on the same axis, and a buffer use coaxial feeder cable containing part 67 for removing a torsion at the time of winding the cable 7.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a storage structure for use as a motor antenna without losing the characteristics of a vehicle-mounted diversity antenna such as an antenna for a car telephone.

[Prior art]

2. Description of the Related Art Conventionally, there is a spatial diversity antenna in which two antennas are arranged vertically in order to improve reception sensitivity as an antenna for mobile communication. In recent years, in quasi-microwave communications including car phones,
Vehicles are increasingly being used as mobile stations. Further, as a structure for improving the communication quality, Japanese Patent Application Laid-Open No. 59-97207 and Japanese Patent Application Laid-Open No. 60-24940
As disclosed in Publication No. 3, various diversity reception methods have been considered on the mobile station side of a vehicle.

[Problem to be solved by the invention]

When a diapersity antenna is mounted on a vehicle, if it is constantly protruding from the vehicle in which it is mounted, it will be necessary to remove the antenna, for example, when washing the vehicle or putting it in the garage, which is cumbersome and may cause damage. There is also a risk of dragon theft and intentional damage. The present invention has been made in order to solve the above problems, and its purpose is to provide an antenna that can be stored inside a vehicle as needed, and that allows the outer diameter of the antenna to be reduced without spoiling the aesthetic appearance. Another object of the present invention is to provide a vehicle-mounted diversity antenna which has a good diversity effect by adopting a configuration in which a power feeding part matches the antenna when exhibited. [Means for Solving RMA] The structure of the invention for solving the above problem includes a sleeve antenna disposed in the upper stage, and a sleeve antenna disposed in the lower stage, the sleeve antenna being slid and housed in an electrically insulated state. a cylindrical monoball antenna, an inner cylindrical tube made of a conductor that slides and accommodates the monoball antenna in an electrically conductive state, and an outer cylindrical tube made of a conductor that coaxially surrounds the outside of the inner cylindrical tube. a double cylindrical storage section; a feeder cable for power feeding that passes through and connects the monoball antenna and the inner space of the inner cylindrical tube of the storage section and feeds power to the sleeve antenna; and an outer cylindrical tube of the storage section. , a through hole is provided at a predetermined position with a predetermined impedance matching, and the center coaxial side is connected to the inner cylindrical tube of the storage part and the ground side is connected to the outer cylindrical tube of the storage part from the through hole to supply power to the monoball antenna. and an antenna drive device for storing the sleeve antenna and the monoball antenna in the storage section or extending them from the storage section using a rack cable arranged on the sleeve antenna. .

[Effect]

A sleeve antenna is installed on the upper stage and a monoball antenna is installed on the lower stage.The antenna drive device stores or moves the sleeve antenna into the internal space of the monoball antenna by pulling in or pulling out the rack cable installed in the sleeve antenna. The monoball antenna is extended from the space, and is further stored in or extended from the storage section provided in the vehicle body along with the monoball antenna. The storage part has a double cylindrical structure consisting of an inner tube and an outer tube made of a conductor that always maintains electrical continuity with the monoball antenna, and the power supply to the monoball antenna is provided in the outer tube of the storage portion. This is done by connecting the center coaxial side of the power feeder cable to the inner tube through the through hole, and connecting the ground side to the outer tube. Therefore, it is easy to set the above-mentioned through hole for connecting the center coaxial side of the feeder cable that feeds power to the monoball antenna at a position where a predetermined impedance matching can be achieved, and a good diversity effect is achieved when the antenna is extended. becomes.

【Example】

The present invention will be described below based on specific examples. FIG. 1(a) is a front view showing the configuration of a vehicle-mounted diversity antenna according to the present invention, and FIG.
a) Enlarged detailed view of part B, Figure 1(e) is the same as Figure 1(a)
FIG. 2 is a cross-sectional view taken along line II of FIG. 1 is an upper sleeve antenna, 2 is a lower monoball antenna, and is a vehicle-mounted diversity antenna 10.
It constitutes 0. 3 is the coaxial inner conductor of the sleeve antenna 1, 4 is its radiating part, and 5 is its λ/4 super top. The radiating part 4 and the λ/4 super top 5 form a λ/2 dipole antenna. is forming. Here, λ indicates the wavelength of the center frequency of the communication frequency band. Reference numeral 6 represents a connection member with the coaxial feeder cable 7, and reference numeral 8 represents a resin radome of the sleeve antenna 1. Reference numeral 38 denotes a cylindrical tube of the monoball antenna 2, which has a length of λ/4, and uses the vehicle body as a ground plane to form a dipole type antenna of λ1/2 according to the principle of mirror image. The above λ1 may be the center frequency of the communication frequency band or the center frequency of the mobile station reception band. The radome 8 overlaps the upper end 53 of the cylindrical tube 38, and a conductor or resin cylinder 18 is inserted and fixed to the outer periphery of the radome 8 at the overlapped portion, and the outer diameter is the same as that of the cylindrical tube 38. It is slightly smaller than the inner diameter of the cylindrical tube 38, and is set to be able to slide smoothly inside the cylindrical tube 38. Further, the upper end surface of the cylindrical tube 38 is provided with a hole 54 having a diameter slightly larger than the outer diameter of the radome 8 and smaller than the outer diameter of the cylinder 18. Therefore, the radome 8 at the upper end of the cylinder 18 does not protrude from the hole 54 at the upper end of the cylindrical tube 38 . The cylindrical tube 38 serving as the monoball antenna 2 overlaps the upper end 56 of the storage tube 55 that constitutes the inner cylindrical tube of the storage section, and a cylindrical conductor tube 57 is attached to the outer periphery of the cylindrical tube 38 at the upper end 56. It is inserted and fixed, and its outer diameter is the same as that of the storage tube 5.
5, and is set to be able to slide smoothly inside the storage tube 55. Further, the upper end surface of the storage tube 55 is provided with a hole 58 having a diameter slightly larger than the outer diameter of the cylindrical tube 38 and smaller than the outer diameter of the cylindrical tube 57 as a conductor. Therefore, at the upper end of the cylindrical tube 57, the cylindrical tube 3
8 does not protrude from the hole 58 at the upper end of the storage tube 55. Furthermore, an antenna top 17 made of resin is provided at the upper end of the radome 8, and its outer diameter matches the hole 58 at the upper end of the storage tube 55.
Since it is larger, the antenna top 17 comes into contact with the upper end of the storage tube 55 during storage, and the radome 8 does not protrude into the storage tube 55 any further. Reference numeral 59 denotes a cylindrical tube that coaxially surrounds the storage tube 55 and constitutes the outer tube of the storage section. There is a short circuit. Further, the upper end of the choke pipe 59 is fixed to the upper end of the storage pipe 55 by a resin ring 60, and the upper end of the choke pipe 59 is connected to the vehicle body and grounded. Reference numeral 61 denotes a hole provided in the vehicle body into which the choke pipe 59 is inserted. 62 is a coaxial connector which is the output terminal of the feeder cable 31 for feeding power from the communication device 29 to the monoball antenna 2; its ground side 63 is connected to the choke tube 59; and its center coaxial side 64 is connected to the choke tube 59. It is connected to the storage pipe 55 through the provided through hole. Reference numeral 68 denotes an output terminal of the sleeve antenna 1, which is connected to a feeder cable 30 for feeding power from the communication device 29. Coaxial feeder cable 7 for sleeve antenna 1 and coaxial feeder cable 7 attached to connecting member 6
A rack cable 20 arranged in parallel with the monoball antenna 2 passes through the cylindrical tube 38 and the storage tube 55 as the monoball antenna 2, and the rack cable 20 stores the sleeve antenna 1 and the monoball antenna 2 in the storage tube 55. Alternatively, it is exposed from the storage tube 55. Reference numeral 65 denotes a drive section constituting an antenna drive device for pulling in or pulling out the rack cable 20. A detailed explanation of the drive unit 65 will be omitted, but it is basically the same as the drive structure of a current radio motor antenna. however,
A winding unit 66 that winds the rack cable 20 and the coaxial feeder cable 7 on the same axis, and the coaxial feeder cable 7
and a buffer coaxial feeder cable storage section 67 that takes care of twisting during winding. Next, in order not to lose its characteristics as a vehicle-mounted diapersity antenna, the coaxial connector 62 is attached to the coaxial tube composed of the choke tube 59 and the storage tube 55 for the monoball antenna 2, so that the impedance of the position is matched. Figure 2(a) shows the conditions. This will be explained with reference to FIG. 2 et al.) and FIG. 2(C). ZA is the antenna impedance seen from P, Zc is the coaxial tube characteristic impedance determined from the inner diameter a1 of the choke tube 59 and the outer diameter of the storage tube 55, and Z (Lc Lp) is the antenna impedance seen from the coaxial connector 62. The impedance, Z(LP), is the impedance in the direction from the coaxial connector to the shorting surface 69. Lc is the length of the choke tube 59, and L is the distance from the shorting surface 69 to the coaxial connector 62. Zl is the impedance seen from the coaxial connector 62. ρ is the VSWR at coaxial connector 62. zo is the characteristic impedance of the feeder cable for power supply from the coaxial connector. Moreover, xL is a reactance component with respect to an inductance component of a portion of the central coaxial side 64 of the coaxial connector 62 connected to the storage tube 55. From this, if the antenna impedance ZA is known, the mounting position of the coaxial tube and coaxial connector can be optimized using the following equation. Z (L P) = j tan (βL F) ZcIn the above formula, L c, L,, Z that suppresses ρ≦1.9
All you have to do is find c. Furthermore, according to experiments conducted by the inventors, the distance Ld between the lower end of the λ/4 super top 5 of the sleeve antenna 1 shown in FIG. 1(a) and the upper end of the monoball antenna 2 is O~ 2
Kyo was the best choice. Furthermore, the length of monoball antenna 2 is (5/8)λ
Alternatively, it may be (6/8)λ. Here, for example, if the length of the monoball antenna 2 is (5/8)λ, the distance between the sleeve antenna l and the monoball antenna 2 can be widened, the correlation can be reduced, and the main beam of the monoball antenna 2 can be The direction can be suppressed to a low level and the antenna gain can be improved. In the above embodiment, the storage tube 55 and the choke tube 59 are configured to be short-circuited at the lower end, but they may be open, and FIGS. 2(a), 2(c), and 2(c) ) can be similarly applied. Furthermore, the storage pipe 55 and the choke pipe 5 in FIG. 1(a)
By filling a dielectric material (relative dielectric constant El) between the rack cable 20 and the coaxial feeder cable 7, the overall size can be reduced by 1/TT. It can be configured compactly. Furthermore, the distance L between the lower end of the λ/4 super top 5 of the sleeve antenna 1 and the upper end of the monoball antenna 2
d may be set as Ld=n·λ. [Effects of the Invention] The present invention provides an antenna drive device that stores a sleeve antenna arranged in an upper stage and a monoball antenna arranged in a lower stage in a storage part or extends it from a storage part by means of a rack cable arranged in the sleeve antenna. , a monoball antenna and a feeder cable for feeding the sleeve antenna which is connected through the inner space of the inner tube of the storage section, and a coaxial side centered on the inner tube from the through hole provided in the outer tube of the storage section; It is equipped with a feeder cable for feeding power to the monoball antenna whose ground side is connected to the outer cylindrical tube, and by feeding power to the monoball antenna from its storage part, the sleeve antenna connects the inner space of the monoball antenna to the sleeve antenna. The monoball antenna can be used through the rack cable and the power feeder cable, and the monoball antenna is stored using the inner cylinder tube of the storage section, so when converting an in-vehicle diapersity antenna into a motor antenna, the outer diameter of the antenna can be adjusted to an aesthetically acceptable level. In addition, the connection positions on the center coaxial side and the ground side of the feeder cable for feeding the monoball antenna can be set regardless of whether the antenna is stowed or exposed, which makes impedance matching for the monoball antenna possible. Since it is possible to remove this, it has the effect that the diaperity effect does not deteriorate.

[Brief explanation of the drawing]

FIG. 1(a) is a front view showing the configuration of a vehicle-mounted diversity antenna according to a specific embodiment of the present invention. FIG. 1(a) is a cross-sectional view taken along line I-1 in FIG. 1(a). FIG. 2(a), FIG. 2(b) and FIG. 2(C) are explanatory diagrams for determining the optimum position for attaching a coaxial connector to a coaxial pipe according to the same embodiment. ■Pass sleeve antenna 2゛/monoball antenna 3-
- Coaxial inner conductor 4° - Radiation part 5 - λ/4 super top 6 - Connection member 7 pa coaxial feeder cable 8... Radome 20 pa - Rack cable 29 - Communication device 30.31°''・Power feeder cable 38 ・°-cylindrical tube 55°° storage tube 5
9...-°Choke tube 62-・Coaxial connector 65-・
Drive unit patent applicant Nippondenso Co., Ltd. Agent Patent attorney Osamu Fujitani 11N -〇No. 1 r＼ 7

Claims (1)

[Scope of Claims] A sleeve antenna disposed in an upper stage; a cylindrical monoball antenna disposed in a lower stage that slides and accommodates the sleeve antenna in an electrically insulated state; and the monoball antenna. a double cylindrical storage section comprising an inner cylindrical tube of a conductor that is slidably housed in an electrically conductive state and an outer cylindrical tube of a conductor that coaxially surrounds the outside of the inner cylindrical tube; the monoball antenna; A through hole is formed at a predetermined position where a predetermined impedance matching is achieved between a power feeding feeder cable that passes through the inner space of the inner cylindrical tube of the storage section and connects it to feed power to the sleeve antenna, and the outer cylindrical tube of the storage section. a feeder cable for supplying power to the monoball antenna by connecting the central coaxial side to the inner tube of the storage section and the ground side to the outer tube of the storage section through the through hole; and a rack arranged on the sleeve antenna. A vehicle-mounted diversity antenna, comprising: an antenna drive device that causes the sleeve antenna and the monoball antenna to be housed in or exposed from the housing part using a cable.